Field of the Invention
The present invention relates to a tool changer provided with covers configured to prevent extraneous matter from getting into a turret.
Description of the Related Art
A tool changer is conventionally used to automatically change a tool to be mounted on the spindle of a machine tool. This tool changer is previously fitted with a plurality of necessary work tools such that the tool to be mounted on the machine tool spindle can be automatically replaced with a specified one, depending on the machining state.
Japanese Patent Application Laid-Open No. 2010-99766 discloses a machine tool provided with such an automatic tool changer for automatically changing a tool. This tool changer comprises a turret provided with a plurality of grips for gripping the tool.
The automatic tool changer comprises the turret fitted with a plurality of tools such that the turret can be indexed to change the tool mounted on the spindle, whereby the tool can be changed rapidly and accurately. Since the front side of the turret and a turret base are only connected at a distance from each other, however, chips produced during machining and a cutting fluid may possibly get into the turret.
In some cases, therefore, the turret may be provided with cover means that prevents the chips and cutting fluid from getting into the turret during workpiece machining. FIG. 11 shows a prior art example of a machine tool furnished with a tool changer comprising such cover means.
In FIG. 11, an automatic tool changer 2 attached to a machine tool 1 comprises a spindle 3 and a spindle motor 5 for driving the spindle 3. A tool 4 is mounted on the distal end portion of the spindle 3. Further, a Z-axis motor 11 is connected to the spindle 3 by a Z-axis ball screw 10, and the spindle 3 can be driven vertically by the Z-axis motor 11. Furthermore, a turret 6 is provided as a member for changing the tool 4.
The turret 6 is provided with a front cover 61 and a rear cover 62 that eliminate adverse affects on structural parts (not shown) in the turret 6. The front and rear covers 61 and 62 serve to prevent penetration of the chips and cutting fluid from the front and rear sides, respectively, of the turret 6.
Depending on the shape of the rear cover 62, chips and the cutting fluid may easily accumulate on an upper part (corresponding to region A of FIG. 11) of a cylindrical portion 64 of the rear cover 62. In changing the tool 4, the spindle 3 is driven vertically by the Z-axis motor 11. Since the spindle 3 is provided with a cam 7, the turret 6 is swung by a cam follower 8 that follows the cam 7 as the spindle 3 is moved vertically. As the turret 6 is swung in this manner, chips and the cutting fluid deposited on the upper part (regions A) of the cylindrical portion 64 of the rear cover 62 move along path B shown in FIG. 11, and inevitably get into the turret 6 through a gap 65 between the front and rear covers 61 and 62. Consequently, the structural parts in the turret 6 may be adversely affected.